2 # Makefile for the linux kernel signature checking certificates.
5 obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
7 ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y)
9 $(eval $(call config_filename,SYSTEM_TRUSTED_KEYS))
11 # GCC doesn't include .incbin files in -MD generated dependencies (PR#66871)
12 $(obj)/system_certificates.o: $(obj)/x509_certificate_list
14 # Cope with signing_key.x509 existing in $(srctree) not $(objtree)
15 AFLAGS_system_certificates.o := -I$(srctree)
17 quiet_cmd_extract_certs = EXTRACT_CERTS $(patsubst "%",%,$(2))
18 cmd_extract_certs = scripts/extract-cert $(2) $@ || ( rm $@; exit 1)
20 ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYS),"verity.x509.pem")
21 SYSTEM_TRUSTED_KEYS_SRCPREFIX := $(srctree)/certs/
24 targets += x509_certificate_list
25 $(obj)/x509_certificate_list: scripts/extract-cert $(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(SYSTEM_TRUSTED_KEYS_FILENAME) FORCE
26 $(call if_changed,extract_certs,$(SYSTEM_TRUSTED_KEYS_SRCPREFIX)$(CONFIG_SYSTEM_TRUSTED_KEYS))
29 clean-files := x509_certificate_list .x509.list
31 ifeq ($(CONFIG_MODULE_SIG),y)
32 ###############################################################################
34 # If module signing is requested, say by allyesconfig, but a key has not been
35 # supplied, then one will need to be generated to make sure the build does not
36 # fail and that the kernel may be used afterwards.
38 ###############################################################################
39 ifndef CONFIG_MODULE_SIG_HASH
40 $(error Could not determine digest type to use from kernel config)
43 redirect_openssl = 2>&1
44 quiet_redirect_openssl = 2>&1
45 silent_redirect_openssl = 2>/dev/null
47 # We do it this way rather than having a boolean option for enabling an
48 # external private key, because 'make randconfig' might enable such a
49 # boolean option and we unfortunately can't make it depend on !RANDCONFIG.
50 ifeq ($(CONFIG_MODULE_SIG_KEY),"certs/signing_key.pem")
51 $(obj)/signing_key.pem: $(obj)/x509.genkey
53 @$(kecho) "### Now generating an X.509 key pair to be used for signing modules."
55 @$(kecho) "### If this takes a long time, you might wish to run rngd in the"
56 @$(kecho) "### background to keep the supply of entropy topped up. It"
57 @$(kecho) "### needs to be run as root, and uses a hardware random"
58 @$(kecho) "### number generator if one is available."
60 $(Q)openssl req -new -nodes -utf8 -$(CONFIG_MODULE_SIG_HASH) -days 36500 \
61 -batch -x509 -config $(obj)/x509.genkey \
62 -outform PEM -out $(obj)/signing_key.pem \
63 -keyout $(obj)/signing_key.pem \
64 $($(quiet)redirect_openssl)
66 @$(kecho) "### Key pair generated."
70 @$(kecho) Generating X.509 key generation config
72 @echo >>$@ "default_bits = 4096"
73 @echo >>$@ "distinguished_name = req_distinguished_name"
74 @echo >>$@ "prompt = no"
75 @echo >>$@ "string_mask = utf8only"
76 @echo >>$@ "x509_extensions = myexts"
78 @echo >>$@ "[ req_distinguished_name ]"
79 @echo >>$@ "#O = Unspecified company"
80 @echo >>$@ "CN = Build time autogenerated kernel key"
81 @echo >>$@ "#emailAddress = unspecified.user@unspecified.company"
83 @echo >>$@ "[ myexts ]"
84 @echo >>$@ "basicConstraints=critical,CA:FALSE"
85 @echo >>$@ "keyUsage=digitalSignature"
86 @echo >>$@ "subjectKeyIdentifier=hash"
87 @echo >>$@ "authorityKeyIdentifier=keyid"
90 $(eval $(call config_filename,MODULE_SIG_KEY))
92 # If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
93 ifeq ($(patsubst pkcs11:%,%,$(firstword $(MODULE_SIG_KEY_FILENAME))),$(firstword $(MODULE_SIG_KEY_FILENAME)))
94 X509_DEP := $(MODULE_SIG_KEY_SRCPREFIX)$(MODULE_SIG_KEY_FILENAME)
98 $(obj)/system_certificates.o: $(obj)/signing_key.x509
100 targets += signing_key.x509
101 $(obj)/signing_key.x509: scripts/extract-cert $(X509_DEP) FORCE
102 $(call if_changed,extract_certs,$(MODULE_SIG_KEY_SRCPREFIX)$(CONFIG_MODULE_SIG_KEY))